Influence of air annealing on the luminescence dynamics of HPHT nanodiamonds

0470965 - FZÚ 2017 RIV CH eng J - Journal Article
Salava, J. - Trojánek, F. - Stehlík, Štěpán - Varga, Marián - Rezek, Bohuslav - Malý, P.
Influence of air annealing on the luminescence dynamics of HPHT nanodiamonds.
Diamond and Related Materials. Roč. 68, Sep (2016), s. 62-65. ISSN 0925-9635. E-ISSN 1879-0062
R&D Projects: GA ČR GA15-01809S
Institutional support: RVO:68378271
Keywords : nanodiamond * time-resolved spectroscopy * annealing * carrier dynamics * high-pressure high-temperature nanodiamonds
Subject RIV: BH - Optics, Masers, Lasers
Impact factor: 2.561, year: 2016

We present a study of the influence of air-annealing on the photoexcited charge carriers dynamics on the surface of nanodiamonds of sub-10 nm size. Samples were produced by high temperature annealing of high-pressure, high-temperature nanodiamonds. Measured photoluminescence spectra of annealed nanodiamonds show distinct blue shift and spectral narrowing compared to non-annealed reference. Time-resolved measurements revealed a change in relaxation process in the nanodiamond surface layer due to removal of non-diamond carbon phase on the surface. Spectro-temporal evolution takes place during the first 50 ps after photoexcitation suggesting that non-radiative states play a major role in the charge carrier relaxation. The acceleration of high energy states depopulation, observed for the annealed nanodiamonds, suggests gradual inhibition of non-radiative recombination channels (originally present in large numbers in non-annealed sample), which is in a good agreement with the picture of reduction of non-diamond carbon phase.
Permanent Link: http://hdl.handle.net/11104/0268469